Borderline personality disorder (BPD) remains a serious public health problem. Dialectical Behavior Therapy (DBT) is a comprehensive psychosocial treatment that is efficacious for BPD. In Phase I, we will develop and evaluate an innovative computer-based training (CBT) prototype of a subset of DBT skills for mental health providers. The CBT will include exploration and simulation environments to facilitate knowledge transfer. An iterative process will be used throughout all phases of prototype development that relies on extensive collaboration and integration of content from mental health professional clinicians. Feedback during this formative evaluation will be obtained from an advisory board comprised of behavior therapy and DBT experts, and through a series of four focus groups with mental health providers. A randomized controlled feasibility Pilot study (N=40) will then be conducted to determine the prototype's efficacy at improving knowledge and application of the DBT skills subset, as well as learner self-efficacy, acceptability, and satisfaction. In Phase II, we will develop all remaining modules described in Linehan's manual and expand the evaluation component to include testing its use within naturalistic settings. [unreadable] [unreadable]